In this thread a group of -- oh horrors -- three comments, at least one of them potentially quite useful, and not constituting a back&forth between two users, was hidden -- oops, "moved to chat". It seems that this has been happening more often on shorter comment threads, since he recent moderator election. I will be careful to vote next year.
In the meantime, what is the standard for an "extended discussion"? It seems to me that three comments do not qualify, and I see many questions with far more than three comments not moved. They were not comments by me, or I would have reposted them where they belonged.